package com.jml.account.common.entity.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;


public class Base64Util {
        private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
            public static String encode(byte[] data) {
                int start = 0;
                int len = data.length;
                StringBuffer buf = new StringBuffer(data.length * 3 / 2);
 
                int end = len - 3;
                int i = start;
                int n = 0;
 
                while (i <= end) {
                	int d = ((((int) data[i]) & 0x0ff) << 16)
                            | ((((int) data[i + 1]) & 0x0ff) << 8)
                            | (((int) data[i + 2]) & 0x0ff);
 
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append(legalChars[(d >> 6) & 63]);
                    buf.append(legalChars[d & 63]);
 
                    i += 3;
 
                    if (n++ >= 14) {
                        n = 0;
                        buf.append(" ");
                    }
                }
 
                if (i == start + len - 2) {
                    int d = ((((int) data[i]) & 0x0ff) << 16)
                            | ((((int) data[i + 1]) & 255) << 8);
 
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append(legalChars[(d >> 6) & 63]);
                    buf.append("=");
                } else if (i == start + len - 1) {
                    int d = (((int) data[i]) & 0x0ff) << 16;
 
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append("==");
                }
 
                return buf.toString();
            }
 
            private static int decode(char c) {
                if (c >= 'A' && c <= 'Z')
                    return ((int) c) - 65;
                else if (c >= 'a' && c <= 'z')
                    return ((int) c) - 97 + 26;
                else if (c >= '0' && c <= '9')
                    return ((int) c) - 48 + 26 + 26;
                else
                    switch (c) {
                    case '+':
                        return 62;
                    case '/':
                        return 63;
                    case '=':
                        return 0;
                    default:
                        throw new RuntimeException("unexpected code: " + c);
                    }
            }
 
            /**
             * Decodes the given Base64 encoded String to a new byte array. The byte
             * array holding the decoded data is returned.
             */
 
            public static byte[] decode(String s) {
 
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                try {
                    decode(s, bos);
                } catch (IOException e) {
                    throw new RuntimeException();
                }
                byte[] decodedBytes = bos.toByteArray();
                try {
                    bos.close();
                    bos = null;
                } catch (IOException ex) {
                    System.err.println("Error while decoding BASE64: " + ex.toString());
                }
                return decodedBytes;
            }
 
            private static void decode(String s, OutputStream os) throws IOException {
                int i = 0;
 
                int len = s.length();
 
                while (true) {
                    while (i < len && s.charAt(i) <= ' ')
                        i++;
 
                    if (i == len)
                        break;
 
                    int tri = (decode(s.charAt(i)) << 18)
                            + (decode(s.charAt(i + 1)) << 12)
                            + (decode(s.charAt(i + 2)) << 6)
                            + (decode(s.charAt(i + 3)));
 
                    os.write((tri >> 16) & 255);
                    if (s.charAt(i + 2) == '=')
                        break;
                    os.write((tri >> 8) & 255);
                    if (s.charAt(i + 3) == '=')
                        break;
                    os.write(tri & 255);
 
                    i += 4;
                }
            }
             
}